The proposed work involves further investigating the relationship between MLC and CML in humans. We have previously demonstrated that both B and T lymphoblast cell lines (LCL's) can stimulate in MLC and generate effector cells in CML. LCL's fixed with glutaraldehyde also stimulate; however, normal peripheral blood lymphocytes cannot. We are currently attempting to determine the differences between normal lymphocytes and LCL's which allow the LCL's to stimulate and not normal lymphocytes. BIBLIOGRAPHIC REFERENCES: D.M. Callewaert, J. Kaplan, W.D. Peterson, Jr., and J.J. Lightbody, Stimulation in Mixed Leukocyte Culture and Generation of Effector Cells in Cell Mediated Lympholysis by Human T Lymphoblast Cell Line, Cellular Immunology, 19, 276, 1975. D.M. Callewaert, J. Kaplan, W.D. Peterson and J.J. Lightbody, Suppression of Lymphocyte Activation by a Factor Produced by Mycoplasma Arginine, Journal of Immunology, 115,1662, 1975.